Triply-Linked Porphyrin−Norcorrole Hybrid with Singlet Diradical Character

Norcorrole Ni(II) complexes have recently received considerable attention as readily accessible antiaromatic molecules. Their high stabil-ity under ambient conditions and easy synthesis have enabled the exploration of the intrinsic properties of antiaromatic molecules. Here, we report the synthesis and properties of directly meso−meso singly-linked porphyrin−norcorrole hybrids and triply-linked porphy-rin−norcorrole hybrids. The singly-linked and triply-linked porphyrin−norcorrole hybrids were fully characterized, including their X-ray structural analysis. Because of their orthogonal conformation, singly-linked hybrids maintained the individual electronic property of por-phyrin and norcorrole subunits The triply-linked hybrid showed a significant decrease in the HOMO–LUMO gaps, the paratropic ring current in the norcorrole subunit, and the diamagnetic ring current in the porphyrin subunit. Furthermore, the triply-linked hybrid exhib-ited singlet diradical characteristics, confirmed by VT-NMR, ESR, and SQUID experiments.